The complete review considers a wide variety of books, including many that are not reviewed in your usual Sunday supplement.
We have books under review that have been out of print for years or decades -- or that you have simply never heard of.
This list only gives the obscurest of these (and none of those that have not been translated into English (remember to check out the foreign books we have under review for those)).
Here is our selection of the most obscure books currently under review, ranked in some order of how unlikely it is that you ever heard of them (or can find a copy):

Yuri Andrukhovych's Recreations -- a leading Ukrainian author, but not (yet ?) well-known in the US

Philipp Blom's The Simmons Papers -- Faber & Faber published this (and it might have remained in print for a week or so), and we even own a copy, but we are still not convinced it actually exists -- except, bizarrely, in a German translation

Jens Bjørneboe's Without a Stitch -- once controversial but now -- despite the art-house stills from the movie -- of little interest, despite the fact that its author produced other very impressive works